[RFC PATCH 0/2] WIP: generic OF pinmux binding

[RFC PATCH 0/2] WIP: generic OF pinmux binding

[Jamie Iles]

To avoid going too far in the wrong direction I thought I'd post what I
have so far for a generic pinmux binding.  Essentially it's just
Stephen's nvidia binding but with the nvidia specifics abstracted out so
the common loop can be used for other platforms.  This approach works
nicely for picoxcell too.

For more esoteric bindings, such as pull strength, these could be
handled in the platform specific configuration function.

This doesn't address the runtime muxing that LinusW's set of patches do,
and I'm not sure how to handle that.

Jamie Iles (1):
  of: add a generic pinmux helper

Stephen Warren (1):
  arm/tegra: Add device tree support to pinmux driver

 arch/arm/mach-tegra/pinmux.c |  240 ++++++++++++++++++++++++++++++++++++++++++
 drivers/of/Kconfig           |    5 +
 drivers/of/Makefile          |    1 +
 drivers/of/of_pinmux.c       |   80 ++++++++++++++
 include/linux/of_pinmux.h    |   67 ++++++++++++
 5 files changed, 393 insertions(+), 0 deletions(-)
 create mode 100644 drivers/of/of_pinmux.c
 create mode 100644 include/linux/of_pinmux.h

-- 
1.7.4.1

[RFC PATCH 1/2] of: add a generic pinmux helper

[Jamie Iles]

This patch adds a helper function of_pinmux_parse() that can be used to
extract common pinmux configuration to avoid each platform implementing
a parsing loop.  Platforms supply the node containing the pinmux
definitions and a platform specific callback for configuring a pingroup.

Cc: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Jamie Iles <jamie-wmLquQDDieKakBO8gow8eQ@public.gmane.org>
---
 drivers/of/Kconfig        |    5 +++
 drivers/of/Makefile       |    1 +
 drivers/of/of_pinmux.c    |   80 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of_pinmux.h |   67 +++++++++++++++++++++++++++++++++++++
 4 files changed, 153 insertions(+), 0 deletions(-)
 create mode 100644 drivers/of/of_pinmux.c
 create mode 100644 include/linux/of_pinmux.h

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index b3bfea5..d300c02 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -87,4 +87,9 @@ config OF_PCI_IRQ
 	help
 	  OpenFirmware PCI IRQ routing helpers
 
+config OF_PINMUX
+	def_bool y
+	help
+	  OpenFirmware pin multiplexing helpers
+
 endmenu # OF
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 74b959c..04d7fa9 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_OF_SPI)	+= of_spi.o
 obj-$(CONFIG_OF_MDIO)	+= of_mdio.o
 obj-$(CONFIG_OF_PCI)	+= of_pci.o
 obj-$(CONFIG_OF_PCI_IRQ)  += of_pci_irq.o
+obj-$(CONFIG_OF_PINMUX) += of_pinmux.o
diff --git a/drivers/of/of_pinmux.c b/drivers/of/of_pinmux.c
new file mode 100644
index 0000000..adfdfc0
--- /dev/null
+++ b/drivers/of/of_pinmux.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2011 Picochip Ltd., Jamie Iles
+ *
+ * Generic pinmux bindings for device tree.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_pinmux.h>
+
+/**
+ * of_pinmux_parse - configure a set of pinmux groups for a pinmux controller
+ *
+ * @controller: the controller to configure the pinmux entries for.  This
+ *	defines the controller device node and the callback for configuring
+ *	the pingroups.
+ *
+ * This helper loops over all of the child nodes of a pinmux controller and
+ * collects the configuration for each pinmux group.  A pinmux group is
+ * defined as one or more pins that are configured to a common function.  This
+ * handles common properties that many platforms may implement, but for
+ * platform specific properties these may be handled in the configure
+ * callback.
+ */
+int of_pinmux_parse(const struct of_pinmux_ctrl *controller)
+{
+	struct device_node *np;
+
+	if (!controller || !controller->pinmux || !controller->configure)
+		return -EINVAL;
+
+	for_each_child_of_node(controller->pinmux, np) {
+		struct of_pinmux_cfg config = {
+			.pin = np,
+		};
+		int ret;
+
+		ret = of_property_read_string(np, "function",
+					      &config.function);
+		if (ret < 0) {
+			pr_err("no function for pingroup %s\n", np->name);
+			continue;
+		}
+
+		if (of_find_property(np, "pull-up", NULL))
+			config.flags |= OF_PINMUX_PULL_UP;
+		if (of_find_property(np, "pull-down", NULL))
+			config.flags |= OF_PINMUX_PULL_DOWN;
+
+		if ((config.flags & OF_PINMUX_PULL_MASK) ==
+		    OF_PINMUX_PULL_MASK) {
+			pr_warn("pingroup %s has both pull-up and pull-down properties - defaulting to no pull\n",
+				np->name);
+			config.flags &= ~OF_PINMUX_PULL_MASK;
+		}
+
+		if (of_find_property(np, "tristate", NULL))
+			config.flags |= OF_PINMUX_TRISTATE;
+
+		pr_debug("configure pingroup %s, func=%s, flags=0x%lx\n",
+			 np->name, config.function, config.flags);
+		if (controller->configure(controller, &config))
+			pr_warn("failed to configure pingroup %s\n", np->name);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_pinmux_parse);
diff --git a/include/linux/of_pinmux.h b/include/linux/of_pinmux.h
new file mode 100644
index 0000000..61f2ab6
--- /dev/null
+++ b/include/linux/of_pinmux.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2011 Picochip Ltd., Jamie Iles
+ *
+ * Generic pinmux bindings for device tree.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#ifndef __OF_PINMUX_H__
+#define __OF_PINMUX_H__
+
+struct device_node;
+
+#define OF_PINMUX_PULL_UP	(1 << 0)
+#define OF_PINMUX_PULL_DOWN	(1 << 1)
+#define OF_PINMUX_TRISTATE	(1 << 2)
+
+#define OF_PINMUX_PULL_MASK	(OF_PINMUX_PULL_UP | OF_PINMUX_PULL_DOWN)
+
+/**
+ * struct of_pinmux_cfg - configuration state for a single pinmux entry.
+ *
+ * @function: the name of the function that the pinmux entry should be
+ *	configured to.
+ * @pin: the device_node of the pinmux entry that should be configured.
+ *	Platform specific properties that aren't in the generic binding may be
+ *	obtained from this device node.
+ * @flags: flags for common pinmux options such as pull and tristate.
+ */
+struct of_pinmux_cfg {
+	const char		*function;
+	struct device_node	*pin;
+	unsigned long		flags;
+};
+
+/**
+ * struct of_pinmux_ctrl - platform specific pinmux control state.
+ *
+ * @pinmux: the pinmux device node.  All child nodes are required to be the
+ *	pinmux entry definitions.  Depending on the platform, this may either be
+ *	a single pin or a group of pins where they can be set to a common
+ *	function.
+ * @configure: platform specific callback to configure the pinmux entry.
+ */
+struct of_pinmux_ctrl {
+	struct device_node *pinmux;
+	int		   (*configure)(const struct of_pinmux_ctrl *ctrl,
+					const struct of_pinmux_cfg *cfg);
+};
+
+#ifdef CONFIG_OF
+extern int of_pinmux_parse(const struct of_pinmux_ctrl *controller);
+#else
+static inline int of_pinmux_parse(const struct of_pinmux_ctrl *controller)
+{
+	return -ENOSYS;
+}
+#endif /* CONFIG_OF */
+
+#endif /* __OF_PINMUX_H__ */
-- 
1.7.4.1

[RFC PATCH 2/2] arm/tegra: Add device tree support to pinmux driver

[Jamie Iles]

From: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

[ j.iles: converted to generic of_pinmux_parse() ]

Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Jamie Iles <jamie-wmLquQDDieKakBO8gow8eQ@public.gmane.org>
---
 arch/arm/mach-tegra/pinmux.c |  240 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 240 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-tegra/pinmux.c b/arch/arm/mach-tegra/pinmux.c
index ed316f9..cd540eb 100644
--- a/arch/arm/mach-tegra/pinmux.c
+++ b/arch/arm/mach-tegra/pinmux.c
@@ -20,6 +20,8 @@
 #include <linux/errno.h>
 #include <linux/spinlock.h>
 #include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_pinmux.h>
 #include <linux/platform_device.h>
 
 #include <mach/iomap.h>
@@ -124,6 +126,21 @@ static const char *pingroup_name(enum tegra_pingroup pg)
 	return pingroups[pg].name;
 }
 
+#ifdef CONFIG_OF
+static int pingroup_enum(const char *name, enum tegra_pingroup *pg_out)
+{
+	int pg;
+
+	for (pg = 0; pg < TEGRA_MAX_PINGROUP; pg++)
+		if (!strcasecmp(name, tegra_soc_pingroups[pg].name)) {
+			*pg_out = pg;
+			return 0;
+		}
+
+	return -EINVAL;
+}
+#endif
+
 static const char *func_name(enum tegra_mux_func func)
 {
 	if (func == TEGRA_MUX_RSVD1)
@@ -147,6 +164,41 @@ static const char *func_name(enum tegra_mux_func func)
 	return tegra_mux_names[func];
 }
 
+#ifdef CONFIG_OF
+static int func_enum(const char *name, enum tegra_mux_func *func_out)
+{
+	int func;
+
+	if (!strcasecmp(name, "RSVD1")) {
+		*func_out = TEGRA_MUX_RSVD1;
+		return 0;
+	}
+	if (!strcasecmp(name, "RSVD2")) {
+		*func_out = TEGRA_MUX_RSVD2;
+		return 0;
+	}
+	if (!strcasecmp(name, "RSVD3")) {
+		*func_out = TEGRA_MUX_RSVD3;
+		return 0;
+	}
+	if (!strcasecmp(name, "RSVD4")) {
+		*func_out = TEGRA_MUX_RSVD4;
+		return 0;
+	}
+	if (!strcasecmp(name, "NONE")) {
+		*func_out = TEGRA_MUX_NONE;
+		return 0;
+	}
+
+	for (func = 0; func < TEGRA_MAX_MUX; func++)
+		if (!strcasecmp(name, tegra_mux_names[func])) {
+			*func_out = func;
+			return 0;
+		}
+
+	return -EINVAL;
+}
+#endif
 
 static const char *tri_name(unsigned long val)
 {
@@ -329,6 +381,22 @@ static const char *drive_pinmux_name(enum tegra_drive_pingroup pg)
 	return drive_pingroups[pg].name;
 }
 
+#ifdef CONFIG_OF
+static int drive_pinmux_enum(const char *name,
+			     enum tegra_drive_pingroup *pg_out)
+{
+	int pg;
+
+	for (pg = 0; pg < TEGRA_MAX_DRIVE_PINGROUP; pg++)
+		if (!strcasecmp(name, drive_pingroups[pg].name)) {
+			*pg_out = pg;
+			return 0;
+		}
+
+	return -EINVAL;
+}
+#endif
+
 static const char *enable_name(unsigned long val)
 {
 	return val ? "ENABLE" : "DISABLE";
@@ -666,15 +734,187 @@ void tegra_pinmux_config_pullupdown_table(const struct tegra_pingroup_config *co
 	}
 }
 
+#ifdef CONFIG_OF
+static int __init tegra_pinmux_dt_configure(const struct of_pinmux_ctrl *ctrl,
+					    const struct of_pinmux_cfg *config)
+{
+	struct tegra_pingroup_config tegra_config;
+	int ret;
+
+	ret = pingroup_enum(config->pin->name, &tegra_config.pingroup);
+	if (ret < 0) {
+		pr_err("invalid pingroup name (%s)\n", config->pin->name);
+		return ret;
+	}
+
+	ret = func_enum(config->function, &tegra_config.func);
+	if (ret < 0) {
+		pr_err("invalid function (%s)\n", config->function);
+		return ret;
+	}
+
+	if (config->flags & OF_PINMUX_PULL_UP)
+		tegra_config.pupd = TEGRA_PUPD_PULL_UP;
+	else if (config->flags & OF_PINMUX_PULL_DOWN)
+		tegra_config.pupd = TEGRA_PUPD_PULL_DOWN;
+	else
+		tegra_config.pupd = TEGRA_PUPD_NORMAL;
+
+	tegra_config.tristate = (config->flags & OF_PINMUX_TRISTATE) ?
+		TEGRA_TRI_TRISTATE : TEGRA_TRI_NORMAL;
+
+	tegra_pinmux_config_pingroup(&tegra_config);
+
+	return 0;
+}
+static void __init tegra_pinmux_parse_mux_groups(
+			struct platform_device *pdev,
+			struct device_node *mux_node)
+{
+	struct of_pinmux_ctrl tegra_pinmux_ctrl = {
+		.pinmux = mux_node,
+		.configure = tegra_pinmux_dt_configure,
+	};
+
+	if (of_pinmux_parse(&tegra_pinmux_ctrl))
+		pr_err("failed to parse pinmux configuration\n");
+}
+
+static void __init tegra_pinmux_parse_drive_groups(
+			struct platform_device *pdev,
+			struct device_node *drive_node)
+{
+	struct device_node *node;
+
+	for_each_child_of_node(drive_node, node) {
+		enum tegra_drive_pingroup pg;
+		enum tegra_hsm hsm;
+		enum tegra_schmitt schmitt;
+		enum tegra_drive drive;
+		enum tegra_pull_strength pull_down;
+		enum tegra_pull_strength pull_up;
+		enum tegra_slew slew_rising;
+		enum tegra_slew slew_falling;
+		int ret;
+
+		ret = drive_pinmux_enum(node->name, &pg);
+		if (ret < 0) {
+			dev_err(&pdev->dev,
+				"(drive) %s: Invalid pingroup name\n",
+				node->name);
+			continue;
+		}
+
+		if (of_find_property(node, "nvidia,high-speed-mode", NULL))
+			hsm = TEGRA_HSM_ENABLE;
+		else
+			hsm = TEGRA_HSM_DISABLE;
+
+		if (of_find_property(node, "nvidia,schmitt", NULL))
+			schmitt = TEGRA_SCHMITT_ENABLE;
+		else
+			schmitt = TEGRA_SCHMITT_DISABLE;
+
+		ret = of_property_read_u32(node, "nvidia,drive-power", &drive);
+		if (ret < 0) {
+			dev_err(&pdev->dev,
+				"(drive) %s: Missing property "
+				"nvidia,drive-power\n",
+				node->name);
+			continue;
+		}
+
+		ret = of_property_read_u32(node, "nvidia,pull-down-strength",
+					   &pull_down);
+		if (ret < 0) {
+			dev_err(&pdev->dev,
+				"(drive) %s: Missing property "
+				"nvidia,pull-down-strength\n",
+				node->name);
+			continue;
+		}
+
+		ret = of_property_read_u32(node, "nvidia,pull-up-strength",
+					   &pull_up);
+		if (ret < 0) {
+			dev_err(&pdev->dev,
+				"(drive) %s: Missing property "
+				"nvidia,pull-up-strength\n",
+				node->name);
+			continue;
+		}
+
+		ret = of_property_read_u32(node, "nvidia,slew-rate-rising",
+					   &slew_rising);
+		if (ret < 0) {
+			dev_err(&pdev->dev,
+				"(drive) %s: Missing property "
+				"nvidia,slew_rate-rising\n",
+				node->name);
+			continue;
+		}
+
+		ret = of_property_read_u32(node, "nvidia,slew-rate-falling",
+					   &slew_rising);
+		if (ret < 0) {
+			dev_err(&pdev->dev,
+				"(drive) %s: Missing property "
+				"nvidia,slew_rate-falling\n",
+				node->name);
+			continue;
+		}
+
+		dev_dbg(&pdev->dev,
+			"(drive) %s: hsm %d schmitt %d drive %d "
+			"pull_down %d pull_up %d slew_r %d slew_f %d\n",
+			node->name,
+			hsm, schmitt, drive,
+			pull_down, pull_up,
+			slew_rising, slew_falling);
+
+		tegra_drive_pinmux_config_pingroup(pg, hsm, schmitt, drive,
+						   pull_down, pull_up,
+						   slew_rising, slew_falling);
+	}
+}
+
+static void __init tegra_pinmux_probe_dt(struct platform_device *pdev)
+{
+	struct device_node *node;
+
+	for_each_child_of_node(pdev->dev.of_node, node) {
+		if (!strcmp(node->name, "nvidia,mux-groups"))
+			tegra_pinmux_parse_mux_groups(pdev, node);
+		else if (!strcmp(node->name, "nvidia,drive-groups"))
+			tegra_pinmux_parse_drive_groups(pdev, node);
+		else
+			dev_err(&pdev->dev, "%s: Unknown child node\n",
+				node->name);
+	}
+}
+#else
+static inline void __init tegra_pinmux_probe_dt(struct platform_device *pdev)
+{
+}
+#endif
+
 static int __init tegra_pinmux_probe(struct platform_device *pdev)
 {
+	tegra_pinmux_probe_dt(pdev);
+
 	return 0;
 }
 
+static struct of_device_id tegra_pinmux_of_match[] __devinitdata = {
+	{ .compatible = "nvidia,tegra20-pinmux", },
+	{ },
+};
+
 static struct platform_driver tegra_pinmux_driver = {
 	.driver		= {
 		.name	= "tegra-pinmux",
 		.owner	= THIS_MODULE,
+		.of_match_table = tegra_pinmux_of_match,
 	},
 	.probe		= tegra_pinmux_probe,
 };
-- 
1.7.4.1

Re: [RFC PATCH 0/2] WIP: generic OF pinmux binding

[Linus Walleij]

On Wed, Aug 17, 2011 at 1:47 PM, Jamie Iles <jamie@jamieiles.com> wrote:

> To avoid going too far in the wrong direction I thought I'd post what I
> have so far for a generic pinmux binding.

It looks like a large part of the binding is about pulling, biasing,
input props like schmitt-triggering and so on, so since I use the
concept of "pincontrol" for all those things in my devised subsystem
can we call them "pincontrol bindings" rather than pinmux,
because pinmux is really just one part of it?

Thanks,
Linus Walleij

Re: [RFC PATCH 0/2] WIP: generic OF pinmux binding

[Shawn Guo]

On Wed, Aug 17, 2011 at 12:47:26PM +0100, Jamie Iles wrote:
> To avoid going too far in the wrong direction I thought I'd post what I
> have so far for a generic pinmux binding.

Unfortunately, there is not much that i.mx iomuxc can leverage, even
for mux-function.  The following is the mux configuration for one
i.mx pin/pad.  Other than a string, a integer will work much better.

MUX_MODE (bit 2-0): Select 1 of 7 iomux modes to be used for pad: EIM_DA9.
000 Select mux mode: ALT0 mux port: WEIM_DA_A[9] of instance: weim.
001 Select mux mode: ALT1 mux port: DISP1_DAT[0] of instance: ipu1.
010 Select mux mode: ALT2 mux port: CSI1_D[0] of instance: ipu2.
011 Select mux mode: ALT3 mux port: DPHY_TEST_OUT[11] of instance: mipi_core.
101 Select mux mode: ALT5 mux port: GPIO[9] of instance: gpio3.
110 Select mux mode: ALT6 mux port: HDATA[23] of instance: tpsmp.
111 Select mux mode: ALT7 mux port: BT_CFG[9] of instance: src.

> Essentially it's just
> Stephen's nvidia binding but with the nvidia specifics abstracted out so
> the common loop can be used for other platforms.  This approach works
> nicely for picoxcell too.
> 
> For more esoteric bindings, such as pull strength, these could be
> handled in the platform specific configuration function.
> 

-- 
Regards,
Shawn

RE: [RFC PATCH 0/2] WIP: generic OF pinmux binding

[Stephen Warren]

Jamie Iles wrote at Wednesday, August 17, 2011 5:47 AM:
> To avoid going too far in the wrong direction I thought I'd post what I
> have so far for a generic pinmux binding.  Essentially it's just
> Stephen's nvidia binding but with the nvidia specifics abstracted out so
> the common loop can be used for other platforms.  This approach works
> nicely for picoxcell too.
> 
> For more esoteric bindings, such as pull strength, these could be
> handled in the platform specific configuration function.
> 
> This doesn't address the runtime muxing that LinusW's set of patches do,
> and I'm not sure how to handle that.

Just FYI, I'm at LinuxCon this week, so probably won't get a chance to
really look over these patches in detail until next week; I can't do them
justice at midnight:-)

-- 
nvpublic

RE: [RFC PATCH 0/2] WIP: generic OF pinmux binding

[Stephen Warren]

Jamie Iles wrote at Wednesday, August 17, 2011 5:47 AM:
> To avoid going too far in the wrong direction I thought I'd post what I
> have so far for a generic pinmux binding.  Essentially it's just
> Stephen's nvidia binding but with the nvidia specifics abstracted out so
> the common loop can be used for other platforms.  This approach works
> nicely for picoxcell too.
> 
> For more esoteric bindings, such as pull strength, these could be
> handled in the platform specific configuration function.

Thanks very much. These patches look sane to me. I'll pick them up in my
local tree, enhance them to support the pins/additional-pins property that
I just mentioned in a separate email, retest and repost.

> This doesn't address the runtime muxing that LinusW's set of patches do,
> and I'm not sure how to handle that.

I see that LinusW just posted another version of this. I'll go check that
out too, in case it has any impact on these patches.

-- 
nvpublic